The semiconductor industry has experienced rapid growth due to improvements in the integration density of a variety of electronic components (e.g., transistors, diodes, resistors, capacitors, etc.). For the most part, this improvement in integration density has come from a shrinkage in physical size of a semiconductor process node (e.g., a reduction in the size of the process node toward that of a sub-20 nanometer (nm) node).
Shrinking the semiconductor process node involves a reduction in operating voltage and current consumption of electronic circuits developed in the semiconductor process node. For example, operating voltages have dropped from 5V to 3.3V, 2.5V, 1.8V, and even 0.9V. A wave of mobile device popularity has increased pressure in the industry to develop low power circuits that only drain a tiny operating current from batteries that power the mobile devices. Lower operating current extends battery life of battery-operated mobile devices, such as smartphones, tablet computers, ultrabooks, and the like.
Voltage regulators are circuits that output an ideally constant voltage over a large range of current loads. Many voltage regulators employ negative feedback that senses the current load, and compensates for changes in the current load to maintain a steady output voltage. Typically, a tradeoff exists between output voltage stability and speed in voltage regulator circuits.